The field of production of articles of manufacture and of repair of such articles include many examples of the treatment of one portion of an article while protecting from treatment another portion of the article. Examples of such treatment include applications of coatings, removal of coatings, mechanical and chemical cleaning of surfaces, removal of selected portions of metallic article surfaces by chemical and electro-chemical type processes and change of surface conditions such as by shot peening.
Widely used forms of masking include the application of adhesive tape and the application of hardenable plastic films applied to or flowed upon selected article surfaces to be protected. Frequently, such methods include subsequent trimming of such a protective medium more accurately about the periphery of the surface to be protected. After treatment, the protective films or tapes must be removed. As can be appreciated, such masking methods are time consuming from a labor viewpoint and can allow detrimental penetration of the treating medium beneath the edge of the protective mask. Other forms of masking have included the mechanical clamping of masks about the surface to be protected. These, too, consume excessive labor time to apply and remove.